Enter the correct email address for the blind carbon copy recipient of your message. To enter multiple recipients, separate the email addresses with commas. Use of any other punctuation to separate multiple email addresses will result in an error.
Blind carbon copies are usually sent to recipients who may need to read what is being written WITHOUT the other recipients knowing that they are receiving the email. Thus "blind" means that the identity of these recipients is hidden from all other recipients of the email. Only you the sender and the "Bcc" recipients will know that they received a copy.